U.S. Pat. No. 6,613,209 discloses a toner characterization cell adapted to determine characteristics of insoluble particles in a liquid medium by measuring an electric displacement current between a first and a second electrode and by measuring optical densities at the first and second electrodes.
Many liquids containing insoluble particles, such as liquid toners, show non-Newtonian behavior. Typically, the viscosity of non-Newtonian fluids is dependent on shear rate or shear rate history. This non-Newtonian behavior often leads to sedimentation problems when the liquid has to flow through a channel.